1. Field of the Invention
The present invention generally relates to a device for the treatment (ostheosynthesis) of proximal humerus fractures, i.e., of the humerus head and neck, to mend and fix in the correct position fractures having one or more fragments.
The device is particularly suitable for the treatment of the proximal humerus fractures of the III or V type according to the Neer classification.
The device generally comprises a body, or plate being substantially spoon-shaped, i.e., comprising
a blade-like proximal portion intended to match the humerus head and provided with at least one seat to insert a threaded wire, a nail, or a similar element to stabilize the fracture, and
a plate-like distal portion, having an elongate shape, intended to match the humerus neck and provided with at least one seat to insert a screw or similar element to fix the body to the humerus.
2. Description of the Related Art
As it is well known in the field, the humerus, and particularly the proximal portion thereof comprising the head and the neck, is considered as a fragile bone, particularly subject to fractures, mainly in people affected by osteoporosis.
Generally these fractures involve the formation of a plurality of fragments and fissures having different features from each other, substantially depending on the bone composing structure, the patient's age and the trauma type.
To compact the plurality of fragments and allow the ostheosynthesis thereof, the use of a plate being substantially spoon-shaped is widespread since a long time, which has a uniform and relatively reduced thickness of about 1-2 mm to tenderly match the proximal humerus, and particularly on the periosteous membrane thereof.
The plate comprises a blade-like proximal portion, wherein one or more seats are obtained to insert nails or threaded wires and a plate-like elongate distal portion wherein one or more seats are obtained to insert fixing screws.
Once mounted, the distal portion fits in the humerus neck and it is fixed therein by means of fixing screws, while the proximal portion fits in the humerus head below the big tubercle.
Afterwards, according to the occurred fracture, one or more threaded wires or nails are inserted in the corresponding proximal portion seats, penetrating the humerus head to make a structure compressing the bone fragments therein.
The threaded wire location and orientation depend on the type of fracture being occurred.
Known devices, although responding to the scope of allowing the ostheosynthesis, have however known still-unsolved drawbacks.
The main drawback is that the humerus scheletric tissue, mainly in case of heavy osteoporosis, undergoes a bone mass loss, especially of the spongious bone mass, with a considerable consistency reduction. A risk of loss of stability of the structure formed by the wires inserted in the humerus head and, consequently, also an insufficient fragment stability result therefrom, with a loss of resistance to physiological as well as traumatic stresses.
This involves the risk that the plate, because of the stresses undergone by the bone, tends to lose the adhesion with the humerus, determining a progressive weakening of the fixing thereof. A period revision of the plate functionality, or eventually a replacement thereof, is thus necessary.
The technical problem underlying the present invention is thus to provide a device for the ostheosynthesis of proximal humerus fractures overcoming the above-mentioned drawbacks of known devices so as to ensure a plate greater application stability in time.